eyy, i' pretty sure their is a kit for the gpx/jailing engine that fits, i recall my loncin being 13mm pin, with 57.4 stroke, and small valves its very simular to the gpx, but the clutch is on the crank and the stud patten is abit diffrent, so it needs to be drilled out
hahahaha...did you see his ---> ...spent a bit over $3000 on bike mostly on motor running around 15-16 horse power maby more. ...yeah right...with *****(TDR)parts...some people simply don't get it